DSLR Photography Forum

Further to R's "Floodlit Cross", I was there too, here are a couple of shots:







Jan

Love numbers 2 and 3. What sort of exposures weere used?

Thanks Bob

No 2 was 8 seconds at f8 and No 3 was 10 seconds, also f8.

Here's one more I quite like:



Jan

PS We seem to have lost the warm, wet and murky weather now, first real crisp frost tis morning!

Great shots. Long exposures are an experiment I haven't tried. Well I won't be trying it this winter.

--Don

All of them have very nice colors... My fav. is #2 because of the light in the headstone.. and the #4 because of the colors and light in the plants...
Very nice pictures NN...

Awrighty!
Is there any noise increase or reciprocity stuff going on when doing long exposures...?

Thewse are all very cool - personal favs are #2 and #3 in original post.

Thanks for your comments Don, Irma and Toad!

Zig: Reciprocity failure in its true sense, (colour shifting), isn't a problem with long exposures on digital as it's caused by the changing properties of film emulsion when exposures exceed tolerances. Increased sensor noise can be a bit of an issue, but when taking long exposures is minimised greatly by the fact that use of tripod/cable release means you can use the slowest available ISOspeed. DSLRs also have a noise reduction facility which is very effective. As far as I know they all work pretty much the same way in that after the shot has been exposed the camera then exposes a further frame at the same shutter speed, but with the shutter closed, (a "dark" frame). This frame only captures the noise generated by the exposure time, and the two frames are compared by the camera which then subtratcts the noise from the actual picture, thereby removing the noise. The only real drawback to this is that every shot takes twice as long, so I have my Pentax set to only use NR if the exposure time is more than 3 seconds.

None of the pics above have had any noise reduction applied in post-processing so here's a 100% crop from one of the pics showing the actual noise level as it came from the camera:



Jan

ta mate!

Noise looks pretty good! (Haha, read that out of context and you'll probably think I'm crazy)

Actually I thought the dark frame subtraction type Noise Reduction was more to get rid of the hot pixels, rather than the actual noise...

As far as I know hot pixels are just VERY noisy pixels. The noise in long exposures like this is generated by the current in the CCD itself....some pixels are worse at collecting current than others and really glow or become "hot", but dark frame subtraction in camera removes both types of noise.

--NN